American 2-4-4T

 

15/02/2011

Over the last few weeks, my brother and I have been helping a friend to sort out the garage contents of a model engineer who passed away last year. The amount of stuff that the chap had accumulated was unbelievable! Apart from three lathes, two milling machines, a shaper, etc. etc. there are sets of laser cut frames and castings for about eight locos!

There are also three complete 5 inch gauge locos, a 2-6-2 tank loco which the family are keeping, an 0-4-0 saddle tank loco, and a very strange American looking tank loco with a 2-4-4 wheel arrangement. My brother took a fancy to this as a restoration project. It is in complete but very dirty and scruffy condition. Closer inspection revealed that it had a steel boiler which is probably bad news. Anyway, my brother made an offer for the loco based on the fact that the boiler was probably scrap and would need to be replaced, and it was accepted.

I did a bit of research on the internet before my brother decided to buy it and it seems the loco is loosely based on an American Forney type loco. These were designed with a 4 wheel bogie under the cab/tender which allowed the locos to negotiate tight curves. They were often of a 0-4-4 wheel configuration and used on ground level and elevated commuter railroads in the American cities. The coal and water capacity was low but this did not matter for the short journeys they were designed to handle.

This loco is unusual in having outside Stephenson valve gear operated by a steam reverser. The cylinders are decidedly British looking rather than American with their square valve chests on top of the cylinders.

A few photos which were taken whilst the loco was still inside the garage so are a bit dark.

View of the cab

Outside Stephenson valve gear

Trailing truck

There is a balloon stack type chimney (visible on the floor behind the loco) that appears to be machined from solid steel and weighs several pounds!

We are collecting the loco this Friday (18th) and my brother will be keeping it at his house during the rebuild, so I probably won't get chance to add photos very often. The first job will be to strip the boiler off and see if there is any chance of reusing it.

20/02/2011

Well, we managed to get 'the beast' home on Friday without too much trouble. My brother bought a folding motorbike ramp which made it easy to run the loco up into the back of the car. He's going to fit rails to the ramp to make it even easier. We can then use it to run the loco out of the car straight onto the traverser at the club. Just as well because it's much too heavy for even two people to lift!

It's now sat on the floor in his house and he's been having a closer look at it and doing a bit of cleaning up. He says it all looks very well made and the photos show this as well. One interesting thing he found out (and we never noticed) is that are no coupling rods between the two driving axles. Instead, there is a chain and sprockets between the frames! Mick discovered this whilst searching for the axle pump, which is right at the front over the front bogie. The frames are solid bar type about 0.5" thick.

We haven't sussed out the steam reverser yet. The operating lever is just to the left of the regulator (visible in the cab photo above) but we don't know if it is possible to actually adjust the cut off or just move between full forward and full reverse. I haven't got a close up photo of the actual reverser but it has two cylinders, one larger than the other. There seems to be a steam feed straight to the cylinders and two from the control valve (presumably forward and reverse).

The steam reversers that I have seen have the control valve actually mounted on the cylinder and controlled by a reach rod and small version of a conventional pole reverse in the cab. The cylinder acts as a servo and the piston follows the movement of the control valve. Move the valve and the piston moves until it matches the position of the valve. This one must work differently.

The steam feed to the control valve seems to come from the regulator housing so whether it only operates when the regulator is open only time will tell! Apparently, the oil feed from the mechanical lubricator comes back to the cab and also feeds into the regulator. The loco is unsuperheated so feeding the oil into the regulator won't be a problem as it won't get hot enough to carbonise. There is the usual steam header on the front tubeplate so the main steam pipe must run through the boiler as normal. There seems to be a connection to the regulator on the right hand side that goes into the boiler and I wonder if that is the steam feed from the dome?

The cylinder drain cocks are operated by a single valve mounted under the left hand footplate and operated by a lever just in front of the cab. The blower valve is also outside, just in front of the cab, although it may be fed via one of the valves on the turret as well.

Water feeds are by an axle pump, hand pump ( mounted on the right hand side of the loco above the rear driver and operated via a linkage from a lever in the cab), and a conventional injector.

Altogether, it's a very interesting and unusual find. The widow managed to find the boiler certificates for all the locos and the one for this loco was from 1992! It was issued by the Derby SMEE, of which the owner was a member, and records a hydraulic test to 150psi for a working pressure of 75psi. It's stated that the boiler is mild steel with copper tubes. There are no other tests shown apart from the one so it's possible that it has not been run since then.

Mick's going to give the boiler a hydraulic test and then try steaming it and blowing down the boiler a few times to see what comes out. I did drain a bit of water out before we brought it home and, much to my surprise, it was perfectly clean with no signs of rust at all.

21/02/2011

I've done a bit of 'Googling' on power reversers this morning and it looks like the reverser is based on the early type patented by William P. Henszey in 1882. This has two cylinders on a common piston rod. The first is the steam cylinder which is connected to the control valve and can be moved backwards and forwards by operating the valve. The second cylinder contains oil and both ends are connected by a valve. When the valve is open, the oil can move freely from one end of the cylinder to the other and so the piston can move. When the valve is shut, the oil cannot flow and the piston is locked in position.

To operate the reverser, the oil valve is opened and the position of the piston in the steam cylinder (and hence the cut off) is set using the control valve. Once the desired position is reached, the oil valve is shut and therefore the reverser pistons are locked in that position.

There is a valve at the far left of the cab that looks 'oily' and I reckon that is the oil valve for the oil cylinder on the reverser.

This type reverser was first used by the likes of James Stirling and finally by Bulleid on the Merchant Navy etc. They were prone to problems with creep and unwanted movement (sometimes violent!) if the seals on the oil cylinder etc. started to leak.

04/03/2011

Mick gave the boiler a quick test last week and then steamed it. Everything was fine except for a slight weep at 100psi on one of the tubes on the front tubeplate.

He's now stripped the boiler off the loco to give it a good looking at. It would appear to be in very good condition still with no serious corrosion inside. I suggested he check to see if there was any sludge on top of the foundation ring and apparently there isn't any, which surprised me. A chap at the club has lent him an endoscope so he can now have a good peer around inside!

The only problem at the moment seems to be the leaking tube. Mick reckons the tubes are silver soldered into the front tubeplate but expanded into the firebox tubeplate. I came across a cure for leaking tubes on Michael Guy's website so we are going to try that. Basically, all you do is dry the boiler off thoroughly and coat the offending leak with Loctite 290, which is a wicking grade thread lock/sealant. The Loctite soaks into the crack and permanently seals it. It helps if you can get a slight vacuum inside the boiler when you do this which obviously helps the Loctite to seep through the crack.

I mentioned this at the club and one of the other members said that a friend of his had done a similar thing with a full size steam roller boiler that had a leaking tube. He didn't know what grade of Loctite the roller owner had used but obviously the cure works. I had a look on the Loctite website and it gives one of the uses for 290 as for sealing porous welds.

I found a seller on Ebay selling 10ml bottles of ex MOD 290 for £1 each so bought two. It's cheap because it's out of date but that doesn't matter - it doesn't go off. Someone told me ages ago that they attended a talk by a chap from Loctite and he said the only reason they put expiry dates on the products was to satisfy the likes of Rolls Royce!

20/03/2011

We took the boiler to the club today so that our club boiler inspector could give it the once over. It weighs a ton being made from 1/4" (6mm) steel plate and tube. It's the first time I've seen it 'naked' and frankly it looks virtually brand new.

The boiler inspector was intrigued as he'd never seen a 5" gauge steel boiler before, only copper ones. With the price of copper now, I suggested he'd be seeing a few more in the future! He was very impressed by the quality of the welding which is very good. I wish mine were half as good!

Anyway, he was more than happy with the construction of the boiler and quite happy to test it. He pumped it up to 220psi, which is nearly 3 times working pressure, just to be on the safe side and it was as tight as a drum with not a single drip from anywhere, not even the suspect tube. Consequently, he gave it a full two years hydraulic certificate so we're in business! As he said, it would happily take 500psi!

Fortunately, our boiler tester is one of those who utilises common sense. I am sure that if it had been another club, things wouldn't have come out so rosy. I'm afraid that some boiler testers are getting ridiculously strict nowadays and condemning perfectly good boilers for no valid reason (gets off soapbox!)

We also took the chassis along for other members to look at so I took the chance to take a few photos before it all goes back together.

The valves and pistons seem to seal very well. If you push the chassis along you can feel the compression in the cylinders and if you let go, the chassis runs back under the air pressure in the cylinders.

Unfortunately, I forgot to take an overall photo of the chassis. It's quite short and only extends from the boiler throatplate to the front buffer beam. The boiler firebox forms the rest of the frames and the rear bogie etc is bolted on to the brackets welded to the sides of the boiler.

Hopefully, it will all be back together in a week or so and we'll be able to give it a proper run under steam, possibly the first time for 20 years!

01/02/2012

The Forney has been steamed many times now and has proved to be a really nice engine. It's very easy to drive with a nice gentle regulator but plenty of power when you need it. We've done quite a bit of passenger hauling on our club running days and the loco handles that with no problems. The boiler pressure seems very stable, possibly due to the steel boiler with it's greater thermal mass than a copper one. The only problem so far was that the ratchet wheel on the lubricator came loose on the shaft but that was soon sorted.

When these photos were taken the loco was running with the temporary chimney used for steaming up but it normally runs with the balloon stack. With the engine not being superheated, the exhaust is very wet!

13/12/2015

Today a friend at the club gave me some very interesting information. He had been looking through some issues of Model Engineer before throwing them away and came across an article by a B. Hatfield describing 'A Simple 2-4-4 Locomotive'. It turns out that the loco described in the article is this Forney. I had had a brief search through the ME indexes in the off chance that I may find something about the loco but hadn't found anything at the time.

 

 

Some enlargements of the photos. Unfortunately, the quality is not that good.

 

 

 

This means the loco is about 50 years old and has undergone a few changes over the years. The original safety valve looks like a Salter type and the original chimney has been lost. The article mentions safety valves so there must have been two originally. The loco has also since gained another dummy dome and the bell. The major change is in the valve gear. It looks as though the original valve gear was a fixed cut off with no expansion link, the valve being driven directly by the return crank on the driving axle with no means of reversing. The outside Stephenson gear was obviously added later along with the steam reverser. Perhaps by a later owner?

It's a real stroke of luck that George found this article. If he hadn't checked before the copies of ME were binned, it would probably have never come to light!

 

15/12/2015

I was interested to see where the Temple Newsam track mentioned in the article was so had a look at an online map. It is near Leeds and I wondered if the track might have belonged to Leeds SMEE. I had a look on their website and they did indeed have a track in Temple Newsam Park from 1960 until 1976 when they moved to a new site at Eggborough power station. The move was instigated by increased vandalism at the park and damage from falling trees. It would appear then that B. Hatfield was an early member of Leeds SMEE.

 

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